Graphic shows the Republican race to win the maximum number of delegates by date and number of delegates per state.

Texas Senator Ted Cruz won the Iowa Republican caucuses, the first vote to choose US presidential candidates. Cruz took 28% of the Republican vote, beating his rival, the frontrunner Donald Trump, and Marco Rubio

The first big day is on March 1 , or Super Tuesday, when 14 states, many in the South, as well as Democrats abroad and Democrats in American Samoa vote.

Top that with the prediction that political ad spending will reach a record high of an estimated $11.4 billion during the year.

Democrat candidates Hilary Clinton and Bernie Sanders face up to five months on the road as they battle to win the support of a majority of delegates in each state to secure the presidential nomination.

The Republican camp includes Ted Cruz, Donald Trump and Marco Rubio.

Candidates must win delegates in each state to capture their nomination for the presidency but with over half the contests held in March, the race could be over well before the Republican Convention in July.